Handlify JSObject::NormalizeProperties method.

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4330 matching lines @@
   if (pt->IsJSProxy()) {
     // We need to follow the spec and simulate a call to [[GetOwnProperty]].
     return JSProxy::cast(pt)->GetElementAttributeWithHandler(receiver, index);
   }
   if (pt->IsNull()) return ABSENT;
   return JSObject::cast(pt)->GetElementAttributeWithReceiver(
       receiver, index, true);
 }
 
 
-MaybeObject* NormalizedMapCache::Get(JSObject* obj,
-                                     PropertyNormalizationMode mode) {
-  Isolate* isolate = obj->GetIsolate();
+Handle<Map> NormalizedMapCache::Get(Handle<NormalizedMapCache> cache,
+                                    Handle<JSObject> obj,
+                                    PropertyNormalizationMode mode) {
   Map* fast = obj->map();
   int index = fast->Hash() % kEntries;
-  Object* result = get(index);
+  Object* result = cache->get(index);
   if (result->IsMap() &&
       Map::cast(result)->EquivalentToForNormalization(fast, mode)) {
 #ifdef VERIFY_HEAP
     if (FLAG_verify_heap) {
       Map::cast(result)->SharedMapVerify();
     }
 #endif
 #ifdef DEBUG
     if (FLAG_enable_slow_asserts) {
       // The cached map should match newly created normalized map bit-by-bit,
       // except for the code cache, which can contain some ics which can be
       // applied to the shared map.
       Object* fresh;
       MaybeObject* maybe_fresh =
           fast->CopyNormalized(mode, SHARED_NORMALIZED_MAP);
       if (maybe_fresh->ToObject(&fresh)) {
         ASSERT(memcmp(Map::cast(fresh)->address(),
                       Map::cast(result)->address(),
                       Map::kCodeCacheOffset) == 0);
         STATIC_ASSERT(Map::kDependentCodeOffset ==
                       Map::kCodeCacheOffset + kPointerSize);
         int offset = Map::kDependentCodeOffset + kPointerSize;
         ASSERT(memcmp(Map::cast(fresh)->address() + offset,
                       Map::cast(result)->address() + offset,
                       Map::kSize - offset) == 0);
       }
     }
 #endif
-    return result;
+    return handle(Map::cast(result));
   }
 
-  { MaybeObject* maybe_result =
-        fast->CopyNormalized(mode, SHARED_NORMALIZED_MAP);
-    if (!maybe_result->ToObject(&result)) return maybe_result;
-  }
-  ASSERT(Map::cast(result)->is_dictionary_map());
-  set(index, result);
+  Isolate* isolate = cache->GetIsolate();
+  Handle<Map> map = Map::CopyNormalized(handle(fast), mode,
+                                        SHARED_NORMALIZED_MAP);
+  ASSERT(map->is_dictionary_map());
+  cache->set(index, *map);
   isolate->counters()->normalized_maps()->Increment();
 
-  return result;
+  return map;
 }
 
 
 void NormalizedMapCache::Clear() {
   int entries = length();
   for (int i = 0; i != entries; i++) {
     set_undefined(i);
   }
 }
 
@@ skipping 12 matching lines @@
     receiver->GetIsolate()->counters()->normalized_maps()->Increment();
     receiver->set_map(*map);
   }
   Map::UpdateCodeCache(map, name, code);
 }
 
 
 void JSObject::NormalizeProperties(Handle<JSObject> object,
                                    PropertyNormalizationMode mode,
                                    int expected_additional_properties) {
-  CALL_HEAP_FUNCTION_VOID(object->GetIsolate(),
-                          object->NormalizeProperties(
-                              mode, expected_additional_properties));
-}
-
-
-MaybeObject* JSObject::NormalizeProperties(PropertyNormalizationMode mode,
-                                           int expected_additional_properties) {
-  if (!HasFastProperties()) return this;
+  if (!object->HasFastProperties()) return;
 
   // The global object is always normalized.
-  ASSERT(!IsGlobalObject());
+  ASSERT(!object->IsGlobalObject());
   // JSGlobalProxy must never be normalized
-  ASSERT(!IsJSGlobalProxy());
+  ASSERT(!object->IsJSGlobalProxy());
 
-  Map* map_of_this = map();
+  Isolate* isolate = object->GetIsolate();
+  Map* map(object->map());

[Toon Verwaest, 2013/09/20 09:32:41]

Handle<Map>

[Michael Starzinger, 2013/09/20 10:46:31]

Done.

[Toon Verwaest, 2013/09/20 09:32:41]

Given that no handle escapes this method, and since there's a loop, lets insert
a new handle-scope here so these handles can be freed after normalizing
properties.

[Michael Starzinger, 2013/09/20 10:46:31]

Done.

   // Allocate new content.
-  int real_size = map_of_this->NumberOfOwnDescriptors();
+  int real_size = map->NumberOfOwnDescriptors();
   int property_count = real_size;
   if (expected_additional_properties > 0) {
     property_count += expected_additional_properties;
   } else {
     property_count += 2;  // Make space for two more properties.
   }
-  NameDictionary* dictionary;
-  MaybeObject* maybe_dictionary =
-      NameDictionary::Allocate(GetHeap(), property_count);
-  if (!maybe_dictionary->To(&dictionary)) return maybe_dictionary;
+  Handle<NameDictionary> dictionary =
+      isolate->factory()->NewNameDictionary(property_count);
 
-  DescriptorArray* descs = map_of_this->instance_descriptors();
+  Handle<DescriptorArray> descs(map->instance_descriptors());
   for (int i = 0; i < real_size; i++) {
     PropertyDetails details = descs->GetDetails(i);
     switch (details.type()) {
       case CONSTANT: {
+        Handle<Name> key(descs->GetKey(i));
+        Handle<Object> value(descs->GetConstant(i), isolate);
         PropertyDetails d = PropertyDetails(
             details.attributes(), NORMAL, i + 1);
-        Object* value = descs->GetConstant(i);
-        MaybeObject* maybe_dictionary =
-            dictionary->Add(descs->GetKey(i), value, d);
-        if (!maybe_dictionary->To(&dictionary)) return maybe_dictionary;
+        dictionary = NameDictionaryAdd(dictionary, key, value, d);
         break;
       }
       case FIELD: {
+        Handle<Name> key(descs->GetKey(i));
+        Handle<Object> value(
+            object->RawFastPropertyAt(descs->GetFieldIndex(i)), isolate);
         PropertyDetails d =
             PropertyDetails(details.attributes(), NORMAL, i + 1);
-        Object* value = RawFastPropertyAt(descs->GetFieldIndex(i));
-        MaybeObject* maybe_dictionary =
-            dictionary->Add(descs->GetKey(i), value, d);
-        if (!maybe_dictionary->To(&dictionary)) return maybe_dictionary;
+        dictionary = NameDictionaryAdd(dictionary, key, value, d);
         break;
       }
       case CALLBACKS: {
-        Object* value = descs->GetCallbacksObject(i);
+        Handle<Name> key(descs->GetKey(i));
+        Handle<Object> value(descs->GetCallbacksObject(i), isolate);
         PropertyDetails d = PropertyDetails(
             details.attributes(), CALLBACKS, i + 1);
-        MaybeObject* maybe_dictionary =
-            dictionary->Add(descs->GetKey(i), value, d);
-        if (!maybe_dictionary->To(&dictionary)) return maybe_dictionary;
+        dictionary = NameDictionaryAdd(dictionary, key, value, d);
         break;
       }
       case INTERCEPTOR:
         break;
       case HANDLER:
       case NORMAL:
       case TRANSITION:
       case NONEXISTENT:
         UNREACHABLE();
         break;
     }
   }
 
-  Heap* current_heap = GetHeap();
-
   // Copy the next enumeration index from instance descriptor.
   dictionary->SetNextEnumerationIndex(real_size + 1);
 
-  Map* new_map;
-  MaybeObject* maybe_map =
-      current_heap->isolate()->context()->native_context()->
-      normalized_map_cache()->Get(this, mode);
-  if (!maybe_map->To(&new_map)) return maybe_map;
+  Handle<NormalizedMapCache> cache(
+      isolate->context()->native_context()->normalized_map_cache());
+  Handle<Map> new_map = NormalizedMapCache::Get(cache, object, mode);
   ASSERT(new_map->is_dictionary_map());
 
-  // We have now successfully allocated all the necessary objects.
-  // Changes can now be made with the guarantee that all of them take effect.
+  // From here on we cannot fail and we shouldn't GC anymore.

[Toon Verwaest, 2013/09/20 09:32:41]

What about putting this into 
{ DisallowHeapAllocation no_allocation;
...
}

rather than having a comment.

[Michael Starzinger, 2013/09/20 10:46:31]

Done. Good point!

 
   // Resize the object in the heap if necessary.
   int new_instance_size = new_map->instance_size();
-  int instance_size_delta = map_of_this->instance_size() - new_instance_size;
+  int instance_size_delta = map->instance_size() - new_instance_size;
   ASSERT(instance_size_delta >= 0);
-  current_heap->CreateFillerObjectAt(this->address() + new_instance_size,
-                                     instance_size_delta);
-  if (Marking::IsBlack(Marking::MarkBitFrom(this))) {
-    MemoryChunk::IncrementLiveBytesFromMutator(this->address(),
+  isolate->heap()->CreateFillerObjectAt(object->address() + new_instance_size,
+                                        instance_size_delta);
+  if (Marking::IsBlack(Marking::MarkBitFrom(*object))) {
+    MemoryChunk::IncrementLiveBytesFromMutator(object->address(),
                                                -instance_size_delta);
   }
 
-  set_map(new_map);
-  map_of_this->NotifyLeafMapLayoutChange();
+  object->set_map(*new_map);
+  map->NotifyLeafMapLayoutChange();
 
-  set_properties(dictionary);
+  object->set_properties(*dictionary);
 
-  current_heap->isolate()->counters()->props_to_dictionary()->Increment();
+  isolate->counters()->props_to_dictionary()->Increment();
 
 #ifdef DEBUG
   if (FLAG_trace_normalization) {
     PrintF("Object properties have been normalized:\n");
-    Print();
+    object->Print();
   }
 #endif
-  return this;
 }
 
 
 void JSObject::TransformToFastProperties(Handle<JSObject> object,
                                          int unused_property_fields) {
+  if (object->HasFastProperties()) return;
+  ASSERT(!object->IsGlobalObject());
   CALL_HEAP_FUNCTION_VOID(
       object->GetIsolate(),
-      object->TransformToFastProperties(unused_property_fields));
+      object->property_dictionary()->TransformPropertiesToFastFor(
+          *object, unused_property_fields));
 }
 
 
-MaybeObject* JSObject::TransformToFastProperties(int unused_property_fields) {
-  if (HasFastProperties()) return this;
-  ASSERT(!IsGlobalObject());
-  return property_dictionary()->
-      TransformPropertiesToFastFor(this, unused_property_fields);
-}
-
-
 static MUST_USE_RESULT MaybeObject* CopyFastElementsToDictionary(
     Isolate* isolate,
     FixedArrayBase* array,
     int length,
     SeededNumberDictionary* dictionary) {
   Heap* heap = isolate->heap();
   bool has_double_elements = array->IsFixedDoubleArray();
   for (int i = 0; i < length; i++) {
     Object* value = NULL;
     if (has_double_elements) {
@@ skipping 11538 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal